Variable displacement vane pumps utilizing two rigid track elements or seal blocks to define a vane tip cam surface or vane tip track are known in the prior art. In such a pump (which is illustrated in U.S. Pat. No. 3,645,652), the track elements may be positioned anywhere between maximum and minimum displacement settings to satisfy flow requirements without mandating undesirable flow bypassing throughout the range of operation.
Conversion of a variable displacement vane pump, as above-described, to a fixed displacement pump can be attained by simply disabling the actuator control system. A converted variable displacement vane pump can, of course, be utilized in any fuel control system which requires a fixed displacement pump but obviously without offering the attendant advantages of a variable displacement pump which prominently include reduced fuel temperature rise at high turndown ratios due to the lack of fuel bypassing.